Wallbie, the Blue Air Wallet, is a virtual placement for your money, similar to a prepaid card. You can deposit money and use it when you want, as a payment method when you book a flight or add some extra services to your current bookings.
Each time you fill your Wallet, you get a bonus, which increases directly with the amount of money you choose to deposit.
For instance, you pay 400 € and you will have 480 € in your Blue Air Wallet (80 € bonus!).